Folding boom for line trucks



Aug. 31, 1954 HURST 2,687,810

FOLDING BOOM FOR LINE TRUCKS Filed April 28. 1953 2 heets-Sheet l my; I 7L INVENTOR. NORMAN F. HU RST ATTORNEY Aug. 31, 1954 N. F. HURST 2,687,810

FOLDING BOOM FOR LINE TRUCKS Filed April 28. 1953 2 Sheets-Sheet 2 INVENTOR.

NORMAN F. HURST ATTORNEY Patented Aug. 31, 1954 Norman Hurst, Aurora, reg., assignor to Ralph M. Osvoldand Norman F. Hurst, aico- ,partnership doing business as: Hurst Truck Utilities, Bortland, Oreg.

Apfllication 'ApliLZS, 1953, Serial No. 351,648

My invention relates to improvements in folding boome -and is particularly adapted to be used inwconnection' with service line trucksrhaving to do with electric transmission lines, telephone lines and the like.

The primary object act the invention is to mount a:liiting:boom onla line truck that can be: automatically stored over the top of the truck while not in use.

Another object of my invention is to be able towoperate the boom by a single hydraulic-cylinder wherein-the loadsbeing lifted by the boom iswsupportediby a connecting rod connected to theapistonrod of the hydraulic cylinderin such a manner thata tension is placed on the rod by the cylinder :while the load is being lifted.

The object ofusing thismethod in supporting the boom under loads is that it is'much safer and eliminates any danger of bucklingthe piston'rod of v the cylinder in the supporting of the load. i,

lIxhave provided means associated with, the cylinder t and connectingrod, of locking the connecting rod to the boomwhile transferringthe boom to its folded or storage position. In'this case "the piston rod performs a pushing action instead of. a- ,pullingrva'ction; thereasonfor this is \that it requires very slittlepmovement'of the rodcto performthe foldingactionof the boom as well the operating action.

These and other incidental objects will be apparent'in the drawings, specification and claims.

Referring-toathe drawings:

Figure 1 is a side sectional view of the body of a, line truck, together with a sectionalview of" my new and improved boom structure.

Figure zillustratesthe'boom in folded position.

Figure 3 is the rear view of Figure 1, partially broken away for convenience of illustration.

Figure 4 is an enlarged detail of the connection between the connecting rod and the piston rod, partially in section, taken on line 4-4 of the broken line position of the boom in Figure 1.

Figure 5 is an enlarged sectional view of the mounting of the boom to the truck, partially broken away for convenience of illustration.

Figure 6 is a plan sectional view, taken on line E-6 of Figure 5.

Figure 7 is a sectional view, taken on line l-! of Figure 3, looking in the direction indicated.

Referring more specifically to the drawings:

The body of a conventional line truck is inv 5 Claims. (Cl. 2128) dicatedbynumeral l andiitrconsists of'sidenwalls 2, usually openedat the rear and having the front wall 3 'Th'eside walls are relativelythick dueato the factthat. shelving. and compartments are built within these :walls for storing equipment.

,I have found that my boom can best be; mounted to the truckuby tway'of the brackets 4. Thesebrackets may consist of channel-like,

members'securedcto the rear endsrof the sides-2 of r the body as well as by the bosses: 5 t to the bottom 6 of the truck by any suitablexmeans as bolts 1.

Bearing; pins "Brand Blaine-fixedly secured between the sides 9 of the brackets '4 and are adapted to support the boom 101m thetfollowing manner: Forminglpart of thezrboom; are jaws Hand I122 While the boom is instoragevposition 'as illustrate'd inFigure 2,'the jaws H engage the cross pin "or bearing-8 and aretlocked thereon by the locking :pin I 3. When the .boom is raised to the position shown in'Figure 1, full lines, the jaw l2 engages thecross pin EA. The locking bolt I3 is then removed from the jaws II and passed through the tips of the jaws I2 for holding these jaws to thepin8A while the boom is in operating position.

A hydraulic cylinder 14 is pivotally mounted to the bracket l5 at t6. Its piston mod I! is pivotally connected at 18 to a connecting. rod I9.

, The/upper end of .the'connecting rod is pivotally connected at 20 to theouter endoftheboom Ill, best, illustrated. in Figures 1and3. The lower end of the connecting rod is secured to the cross'member 2| of theboom while the boom is pivotally connected to the upper :pin '8 as shown in Figures 1,72 and :3. .Thersaid connectingirodhas jaws:22 for engagingthe crossrmember 2|, the said jaws being secured thereto by the locking bolt 23.

When the boom is in Working position, the connecting rod [9 and the piston l4 operate as indicated by the broken lines in Figure 1. While the connecting rod and the piston rod are operating in this position they are locked in alignment by the locking bolt 24, referring to Figure 4 particularly. The connecting rod NJ has an elongated pocket 25 with a bottom 26 against which the piston rod I l engages while being held in the position shown in Figure 4 by the locking bolt pin 24. This maintains the connecting rod and piston in alignment, although there would be other ways of accomplishing this same result.

The usual hoisting gear 21 is mounted in the 3 bottom of the truck with the lifting cable 28 running to the cable sheave 29, terminating in the usual hook 30. The hydraulic cylinder l4 could be located in the broken line position as indicated by numeral 3| in Figure 2.,

I will now describe the operation of my new and improved folding boom for line trucks. When the boom is in folded position the connecting rod I9 is locked to the cross member 2| of the boom [9 by Way of the jaws 22 and the locking bolt 23. When it is desired to raise the boom, hydraulic fluid is applied to the cylinder M, which will push the said boom up, pivoting the same about the pin 8 to the position shown in Figures 1 and 3. This will bring the lower jaws l2 of the boom in registry with the lower pin 8A.

The locking bolt I3 is then transferred from the jaws l I to the jaws [2, locking these said latter jaws to the pivot pin BA. The locking bolt 23 is then removed from the jaws 22 of the connecting rod i9 so that the connecting rod will be released from the cross member 2|. This will permit the connecting rod and piston to assume the broken line position as indicated in Figure 1. Then as the piston rod is pushed out, it will lower the boom as indicated by the broken line position, and it will be noted that this is a direct pull in the supporting of the end of the boom, which it is agreed by linemen is the proper method of supporting the boom with safety, therefore this is one of the outstanding objects of my new and improved boom. It will be noted that little piston travel is required to operatethe same in either the folded position or in operating position.

When the boom is brought to the position shown in Figure 1, full lines, the cable 28 will support the load adjacent the rear of the truck, then all that is necessary to do is to position the same so that it can be pushed into the truck by the workman.

What is claimed is:

1. A folding boom hoisting apparatus comprising a support member, a boom member, releasable pivotal connections between said members at difierent elevations and including horizontal pivots on one of said members and open bear-- ing elements on the other of said elements and respectively cooperative with said pivots, and a fluid operable jack pivotally connected between said members and including a cylinder pivotally mounted on said support member, a piston rod operable in said cylinder, a connecting rod pivotally connected between said boom member and said piston rod, and means cooperative between. said connecting rod and respectively between said boom member and said piston rod for selectively connecting said connecting rod rigidly with said boom member or said piston rod, whereby said connecting rod forms an extension of said piston rod when rigidly connected by said means with said piston rod and the pivotal connection between said piston rod and said connecting rod functions as a pivotal connection between said piston rod and said boom member when said connecting rod is rigidly connected by said means with said boom member.

2. An apparatus as defined in claim 1 wherein said connecting rod is pivotally connected to said boom member adjacent the free end thereof and the distance between the pivotal connections of said connecting rod is shorter than the distance between its pivotal connection with said boom member and the nearest of said releasable pivotal connections.

3. An apparatus as defined in claim 2 wherein said means includes releasable clamp means between said connecting and piston rods for releasably holding said rod in rigid relationship.

4. An apparatus as defined in claim 3 wherein said means includes releasable clamp means between said boom member and said connecting rod for releasably holding said connecting rod in rigid relationship to said boom member.

5. A folding boom hoisting apparatus comprising a supporting structure having a pair of laterally spaced pivot elements aligned along a first horizontal axis, a boom member having two converging legs rigidly connected at their upper ends to each other and being provided intermediate their ends with auxiliary pivot means for permitting the boom to swing about a second horizontal axis spaced upwardly from said first horizontal axis, and a fiuid operable jack pivotally connected between said legs and including a cylinder pivotally mounted on said supporting structure, a piston rod operable in said cylinder, a connecting rod pivotally connected between said boom member and said piston rod, and means cooperative between said connecting rod and said piston rod for selectively connecting said connecting rod rigidly with said piston rod, whereby said connecting rod forms an extension of said piston rod when rigidly connected by said means, and the auxiliary pivot means functions as a pivotal connection when said boom member is being folded and unfolded.

References Cited in the file of this. patent UNITED STATES PATENTS Number Name Date 2,557,466 Richards et al June 19, 1951 2,616,666 Honey Nov. 4, 1952 

